I don’t understand the question but if I can make a correct inference, they have thorns to protect themselves from predators.
The whale's flipper and tail flukes and fish fins are analogous structure as they have different structural formation but they perform the same function.
Flipper and tails are locomotory organs in the whale and helps the whale in propelling similarly fins in the fish assist the fish in swimming. Both the strcutures have evolved differently and are made of different materials.
Explanation:
Naturalists began to focus on the variability of species; the emergence of paleontology with the concept of extinction further undermined static views of nature. In the early 19th century Jean-Baptiste Lamarck (1744–1829) proposed his theory of the transmutation of species, the first fully formed theory of evolution.
In classical Latin, though, evolution had first denoted the unrolling of a scroll, and by the early 17th century, the English word evolution was often applied to 'the process of unrolling, opening out, or revealing'. It is this aspect of its application which may have been behind Darwin's reluctance to use the term.
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Gravity is a force which causes objects to fall or be still on the earth's surface. This invisible force has been longed explored mainly by many scientist however, Isaac Newton was first to conceptualize this into a proper principle.
GravityLight is a device that was recently developed by engineers that is designed to produce light through the force of gravity.
Well the more that get cut down, the less oxygen we get, aswell as more carbon in the atmosphere because there is less trees to absorb it.